1. Field of the Invention
The present invention relates to a thin metallic layer type magnetic recording medium.
2. Description of the Prior Art
The conventional magnetic recording medium has been usually prepared by coating a magnetic composition comprising a binder and a magnetic powder, on a substrate such as a polyester film.
In view of the recent development of magnetic recording apparatuses such as widespread of home VTR and high functional audio cassette, it has been required to attain high density recording over the high density attained by the conventional magnetic recording medium.
A thin metallic layer type magnetic recording medium has been proposed to attain the requirement for the high density magnetic recording. The thin metalic layer type magnetic recording media have been prepared by forming a thin metallic layer on a substrate by forming metallic particles made of a metal or alloy of iron group element or an alloy thereof with the third element by a vacuum evaporation, sputtering, ion-plating, ion beam evaporation or electrochemical method and depositing the metallic particles on the non-magnetic substrate.
It has been known that the thin metallic layer having high coercive force can be formed by depositing the metallic particles (1) on the substrate (2) from the direction having large tilt angle .theta. as shown in FIG. 1 in the step of forming the thin metal layer. In FIG. 1, the normal line to the surface of the substrate (2) is referred as by the reference (3).
Thus, as the common magnetic recording media, it is not always required to have high coercive force in view of the function of the recording systems and it is possible to give certain limited coercive force. In order to satisfy the requirement, it is necessary to give large residual magnetic flux in certain range of the coercive force.